Apparatus to clear control line in well

ABSTRACT

A control line clearing apparatus has a separation sleeve that positions into a downhole element adjacent the element&#39;s control port to which a blocked control line connects. The sleeve separates fluid communication from the control port with the annulus between the sleeve and the downhole element, while still allowing effluents in the well tubing to pass through the interior of the sleeve. A feed line is then lowered into the sleeve, and an automatic coupling on the end of the feed line couples to a coupling member inside the sleeve. Once connected, solvent fed through the feed line communicates with the downhole elements control port via a cross-port in the sleeve. In this way, the solvent can act against the other side of the control line blockage.

BACKGROUND

Various downhole devices use control lines for their operation. As shown in FIG. 1, for example, a control line 40 operates a surface controlled safety valve 20 positioned in a landing nipple 50. The control line 40 conveys control fluid (e.g., hydraulic fluid) to a coupling 42 on the nipple 50, at which point the control fluid can enter a port 24 on the valve 20. Application of pressure in the control line 40 then actuates a piston 26 against the bias of a spring 27 and opens a flapper 28 to allow fluid flow through the valve 20. If uncontrolled flow occurs, release of control fluid pressure causes the flapper 28 to close. Although filters may be used in the control fluid, debris and other material may still collect in the control line 40 and create the potential for clogging or blockage. If this occurs, the safety valve 20 may not operate properly.

Operators must make a number of time-consuming and labor-intensive measures to remedy a clogged or blocked control line 40. For example, operators may have to work over the well and deploy a new safety valve. To avoid the problem altogether, operators may alternatively run a subsurface controlled safety valve instead, but regulations may prevent use of such a valve in a given well. In addition, operators may use a velocity valve in well that does not require control from the surface via a control line. Such velocities valves, however, decrease the production and can be difficult to check once deployed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of a safety valve deployed in a landing nipple in a well.

FIG. 2 is a cross-sectional view of the landing nipple having a clogged or blocked control line with the safety valve components removed.

FIG. 3 shows the landing nipple in which an apparatus to clear the control line is deployed.

FIG. 4 shows a feed line coupling to the apparatus and conveying solvent to clear the blocked control line.

FIG. 5 is an end-sectional view showing the communication of conveyed solvent to clear the blocked control line.

FIG. 6 schematically illustrates a system for clearing a control line according to certain teachings of the present disclosure.

FIG. 7 shows an alternative arrangement for seating the control line clearing apparatus in the landing nipple.

DETAILED DESCRIPTION

In FIG. 1, a landing nipple 50 for a downhole safety valve 20 is shown having a blocked or clogged control line 40 at blockage B near to where the line 40 connects by a coupling 42 to the nipple's port 54. As expected, the blockage B prevents control fluid conveyed from above to pass through the blockage B and operate the safety valve 20. When such blockage occurs, operators remove the safety valve 20 from the nipple 50 through the tubing 10 using standard wireline procedures or the like, leaving the open nipple 50 exposed in the tubing 10 as shown in FIG. 2.

To clear the control line 40, operators then deploy a separation sleeve 100 as shown in FIG. 3. The sleeve 100 is lowered into the nipple 50 using a wireline (not shown) connected to the sleeve's coupling end 104. As it reaches the nipple 50, the sleeve's locking contours 102 engage lock profiles 52 on the inside of the nipple 50 to mechanically seat the sleeve 100 in the nipple 50. When positioned, upper and lower chevrons 105 and 107 on the sleeve 100 seal against the inside of the nipple 50 above and below the control line port 54. In this position, a cross-port 108 on a pod 106 in the sleeve's internal passage 101 aligns with the nipple's port 54.

As shown, a male member 110 of an automatic connector positioned on the pod 106 communicates with the cross-port 108 and extends upward into the passage 101. While the sleeve 100 is in position, any effluents of the well can circulate through the sleeve's internal passage 101 and pass the pod 106, as shown in the end section of FIG. 5.

With the sleeve 100 in position, operators then deploy a capillary string 60 through the tubing 10 as shown in FIG. 4. A latch 70 connects the capillary string 60 to a stinger 120 that has several (i.e., three) centralizing blades 122 to locate the stinger 120 in the sleeve 100. When the stinger 120 is located in the sleeve 100, a female member 130 on the end of the stinger 120 automatically coupes to the male member 110 on the sleeve 100. An example of a suitable automatic connector having members 110 and 130 includes a connector from Staubli of France having male member part no. N01219806 and female member part no. N01219906 and having an exterior pressure rating of about 350 Bar, an interior pressure rating of 550 Bar when coupled, a coupling force of 25 Kg, and a decoupling force of 200 Kg.

Once connected, the capillary string 60 communicates with the sleeve's port 54 via the cross-port 108 in the pod 106. Operators then inject pressurized solvent through the capillary string 60. The solvent reaches the cross-port 108 and fills the sleeve's port 54 as shown in FIGS. 4 and 5. At this point, the solvent reaches the back of any blockage B in the control line 40 and acts against the blockage B to clear the line 40.

To inject the solvent, a system for clearing the control line 40 can be used as schematically illustrated in FIG. 6. As shown, the sleeve 100 deployed within the nipple 50 as discussed previously sealably separates fluid communication between the nipple's control port 54 and the annulus between the sleeve 100 and the nipple 50. In this way, the feed line 60 communicates with the nipple's control port 54 and the control line 40 connected thereto.

Operators use one or more well control panels 200 to apply solvent (e.g., diesel) or other fluid from a solvent reservoir, into the capillary feed line 60, to the control port 54, and into the control line 40 to act against any blockage or clogging. The pressurized solvent can be applied up to the point that the blockage is removed, or it can be passed through the feed line 60 all the way through the control line 40 once any blockage is broken to clear the line of remaining debris. To further work on the blockage, the well control panel 200 can apply pressure alternatingly between the control line 40 and the feed line 60 if the solvent proves slow in relieving the blockage. As opposed to solvent, the well control panel 200 could apply hydraulic fluid through the feed 60 to break the blockage. In addition, once the blockage is cleared, the well control panel 200 can cycle control fluid through the control line 40 and the feed line 60 to flush the control line of debris.

Once the blockage is cleared, operators can reverse the procedures used to install the sleeve 100 in the landing nipple 50. For example, operators disconnect the feed line 60 from the male connector 100 on the sleeve 100 and remove the line 40 from the tubing 10. Then, using wireline procedures, operators remove the sleeve 100 from the nipple 50 and tubing 10 so that the surface controlled safety valve can be redeployed into the nipple 50 using techniques known in the art.

As discussed above, the sleeve 100 can have locking contours 102 for engaging the nipple's lock profiles 52. In an alternative arrangement shown in FIG. 7, the sleeve 100 includes a piston device 140 having locking dogs 142, piston 144, and spring 146 to mechanically seat the sleeve 100 in the nipple 50. When deployed, the wireline attached at the sleeve's end 104 moves the piston 144 so that the dogs 142 engage the lock profiles 52. This piston device 140 can be much like that used with safety valves for installing in a landing nipple with a wireline. The rest of the sleeve 100 remains essentially the same as with the previous embodiments.

Although the present disclosure has been directed to clearing a control line of a safety valve, it will be appreciated that the disclosed apparatus can be used with any downhole component to which a control line connects, including, but not limited to, a remotely operated sliding sleeve, a pressure relief valve, or other downhole device. Although chevrons (e.g., 105 and 107) are described above, it will be appreciated that other devices to sealably engage the sleeve 100 in the nipple 50 can be used, such as elostomer O-rings, packing elements, or crimp seals. Components of the control line clearing apparatus disclosed herein are preferably composed of materials suitable for a well environment and are preferably constructed using accepted practices for the well environment.

The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof. 

1. A control line clearing apparatus, comprising: a body deployable into a downhole element adjacent a control port, the body having an internal passage therethrough and having a port, the port having a first end communicating with the internal passage and a second end communicating outside the body; a first connector disposed in the internal passage of the body and communicating with the first end of the port; and a second connector connectable to a feed line and deployable into the internal passage of the body, the second connector coupleable with the first connector, whereby the feed line is communicable with the control port.
 2. The apparatus of claim 1, wherein the body comprises means for sealably engaging an internal bore of the downhole element on both sides of the control port.
 3. The apparatus of claim 1, wherein the body comprises means for mechanically seating in an internal bore of the downhole element.
 4. The apparatus of claim 1, wherein the body comprises a sleeve having an internal portion of its sidewall disposed in its internal passage to which the first connector connects.
 5. The apparatus of claim 1, wherein the second connector comprises a plurality of blades disposed about the outside of the second connector and locating the second connector within the internal passage of the body.
 6. The apparatus of claim 1, wherein the second connector comprises a female end of an automatic connector.
 7. The apparatus of claim 6, wherein the first connector comprises a male end of the automatic connector.
 8. A control line clearing apparatus, comprising: a sleeve deployable into a downhole element adjacent a control port, the sleeve having an internal passage therethrough and having a port, the port having a first end communicating with the internal passage and a second end communicating outside the sleeve; a first end of an automatic connector disposed in the internal passage of the sleeve and communicating with the first end of the port; and a second end of an automatic connector connectable to a feed line and deployable into the internal passage of the sleeve, the second end coupleable with the first end, whereby the feed line is communicable with the control port.
 9. The apparatus of claim 8, wherein the sleeve comprises first and second chevrons disposed on the outside of the sleeve and sealably engaging an internal bore of the downhole element on both sides of the control port.
 10. The apparatus of claim 8, wherein the sleeve comprises a contour disposed on the outside of the sleeve and seating in a profile of an internal bore in the downhole element.
 11. The apparatus of claim 8, wherein the sleeve comprises locking dogs movable relative to the outside of the sleeve and seating in a profile of an internal bore in the downhole element.
 12. The apparatus of claim 8, wherein the sleeve comprises a seat extending from the sidewall of its internal passage to which the first end of the automatic connector connects.
 13. The apparatus of claim 8, wherein the second end of the automatic connector comprises a plurality of blades disposed about its outside and locating the second end within the internal passage of the sleeve.
 14. The apparatus of claim 8, wherein the second end comprises a female end of an automatic connector.
 15. The apparatus of claim 14, wherein the first end comprises a male end of the automatic connector.
 16. A downhole apparatus, comprising: a nipple deployable downhole, the nipple having a first internal passage therethrough and having a control port communicating the control line with the first internal passage; a sleeve deployable into the first internal passage adjacent the control port, the sleeve having a second internal passage therethrough and having a port, the port having a first end communicating with the second internal passage and a second end communicating outside the sleeve; and a first automatic connector end disposed in the second internal passage of the sleeve and communicating with the first end of the port, the first automatic connector end connectable to a feed line deployable into the second internal passage of the sleeve, whereby the feed line is communicable with the control port.
 17. The apparatus of claim 16, wherein the sleeve comprises first and second chevrons disposed on the outside of the sleeve and sealably engaging the first internal passage of the nipple on both sides of the control port.
 18. The apparatus of claim 16, wherein the sleeve comprises a contour disposed on the outside of the sleeve and seating in a profile of the first internal passage in the nipple.
 19. The apparatus of claim 16, wherein the sleeve comprises locking dogs movable relative to the outside of the sleeve and seating in a profile of the first internal passage in the nipple.
 20. The apparatus of claim 16, wherein the sleeve comprises a seat extending from the sidewall of its internal passage to which the first automatic connector end connects.
 21. A control line clearing method, comprising: deploying a sleeve into a first internal passage of a downhole element; sealably separating fluid communication between a control port on the downhole element to which a control line is connected and the annulus between the sleeve and the first internal passage; establishing fluid communication between a feed line disposed in a second internal passage of the sleeve and the control port of the downhole element; and applying first fluid from the feed line to the control port of the downhole element.
 22. The method of claim 21, wherein deploying the sleeve comprises seating a contour disposed on the outside of the sleeve in a lock profile in the first internal passage of the downhole element.
 23. The method of claim 21, wherein deploying the sleeve comprises seating a movable dog disposed on the outside of the sleeve in a lock profile in the first internal passage of the downhole element.
 24. The method of claim 21, wherein sealably separating fluid communication between the control port and the annulus comprises engaging chevrons disposed on the outside of the sleeve against the first internal passage on both sides of the control port.
 25. The method of claim 21, wherein establishing fluid communication between the feed line and the control port comprises: deploying a first connector on a distal end of the feed line into the second internal passage; mating the first connector to a second connector disposed in the second internal passage, the second connector communicating with the outside of the sleeve adjacent the control port.
 26. The method of claim 21, further comprising alternatingly applying the first fluid via the feed line and second fluid via the control line. 